On the market place, a plurality of foldable boxes or foldable crates is available consisting of a bottom or floor and side walls which are foldable with respect to the floor so that the boxes may be folded after use by folding down their side walls in order for them to be transportable back to the location of their renewed use in a space saving and cost effective way.
High requirements are also directed to the stability of the boxes as the same, for example when transporting fruit and vegetables, are loaded directly at the field by field workers and the vegetables remain within the same box during the complete transport to the end consumer, i.e., the box has to survive the many loading and unloading processes during transport, if possible without getting damaged. Further, the boxes are also used several times according to their purpose which even increases requirements regarding robustness. On the one hand, it is of course very desirable that when keeping side conditions of a weight which is as low as possible, the walls and the floor of the foldable boxes are as robust as possible. Further, due to the plurality of handling processes and actions that may be employed during the transport of such a box, it is to be ensured that normal operation is as easy as possible. It is to be guaranteed simultaneously that in case of erroneous use or operation, the used mechanical components are not destructed. In particular, foldable boxes comprise a locking mechanism by means of which the erected walls are interlocked with each other so that the up-folded box receives the stability necessitated. This locking mechanism should be operable as easily as possible and error-free without much force. However, additionally, the possibility of a wrong operation should be considered, i.e., that a force acts upon the locking mechanism without the same being operated. In this case, the locking mechanism should be destroyed by no means.
A further requirement to such foldable boxes should be that the hinge mechanism which produces a foldable connection between the door and the exterior walls of the foldable box may absorb large forces. The same presents, in the up-folded state, the only non-positive connection between the floor on which usually the complete load is arranged and the exterior walls at which the grip holes are usually located. Even if a robust implementation of a box is used, a destruction of individual components of the box, i.e., in particular of the floor or one of the side walls, may not be excluded in every day use. It is thus desirable that the side walls may easily be detached from the floor without the capability of carrying a high load suffering from the ease of dismantling the non-positive connection.
As such foldable boxes may be used industrially on a large scale and for many different purposes, for example to transport fruit or vegetables from the harvest fields to the consumers, such a foldable box has to fulfill many different requirements which partially influence each other. Some requirements here result from the aspect of transportability. Thus, it is a especially desirable for the box to have only a low stacking height in the down-folded state so that on a pallet during transport a number of down-folded boxes may be transported which is as high as possible. Further, the box ought to be as light as possible, i.e., as little material as possible ought to be used to keep the ratio of the loading capacity or useful load to the weight of the box as low as possible. Apart from this, such boxes are frequently used for the transport of food and it is useful for the interior side of the box to be as smooth or flat as possible so that no food rests will get trapped in the interior of the box. Simultaneously, the box ought to be stable, which makes the use of large flat planes difficult. Further, easy cleaning of the boxes is to be guaranteed which, on the one hand, necessitates flat surfaces and, on the other hand, the possibility has to be given that in automated washing systems cleaning agents or water used during cleaning may run off from the box. This necessitates drain holes or perforations which are, again, in contradiction to the requested high stability. With respect to cleaning, it is especially desirable that at least some of the exterior walls stand on their own in the up-folded state, i.e., remain in the up-folded state, as is useful for successful and thorough cleaning that the complete interior volume of the box is easily accessible.